According to Au7o's research across NHTSA recalls, manufacturer TSBs, and owner forum reports, the 2020 Cadillac CT6 has 5 documented known issues, with 1 rated critical. The most serious is 10-Speed Transmission Damage Can Cause Wheel Lock-Up (Recall 25V148). Across all issues with published estimates, repair costs range from $150 to $1,500. DIY maintenance guides at au7o.io.
On the 2019-2020 Cadillac CT6, certain 2019-2020 Cadillac CT6 vehicles equipped with a 10-speed transmission can develop internal transmission damage that may cause the wheels to lock while driving.
Common Symptoms
Open safety recall
Unexpected wheel lock-up risk
How to Fix
Check the VIN and campaign status. Cadillac dealers install transmission-control-module monitoring software under recall N242480630; follow the campaign instructions if the software detects damage.
On the 2020 Cadillac CT6, gM recalled 2020 Cadillac CT6 sedans fitted with dealer-installed accessory 20 x 8.5-inch wheels (RPO 5JO or SHH) under NHTSA campaign 19V731. The tire pressure monitoring sensors mounted in those accessory wheels transmit on the wrong radio frequency, so the car's TPMS receiver never hears them and the low-pressure telltale cannot illuminate when a tire goes soft. The vehicles fail to comply with FMVSS 138. Only 81 vehicles are affected, which is exactly why it is worth checking: a used 2020 CT6 wearing accessory 20s is the specific car at risk, and a driver can run a badly underinflated tire with no warning at all.
Common Symptoms
Tire pressures show as dashes on the driver information center
Low tire pressure warning never illuminates
TPMS sensors will not relearn
How to Fix
Free recall remedy under NHTSA campaign 19V731 — dealers replace all four TPMS sensors with the correct-frequency units at no charge. If the CT6 you are looking at wears dealer-accessory 20-inch wheels, verify by VIN at nhtsa.gov/recalls that the campaign was completed, and confirm live tire pressures actually display on the driver information center for all four corners rather than reading dashes.
On the 2016-2020 Cadillac CT6, the CT6's rear camera mirror streams a live video feed from a roof-mounted rear camera onto the mirror glass. Owners report the feed going blank, showing a grainy, pixelated or heavily distorted picture, or losing focus so badly at night and in rain that the mirror is unusable. GM addressed the image-quality complaint in TSB 17-NA-375 for grainy, distorted or pixelated rear vision camera images on the CT6, but a share of cars have an outright module or camera failure that dealers resolved by replacing the assembly. Compounding it, using the rear washer sprays fluid onto the camera lens and smears it, and moisture accumulation defeats the lens's hydrophobic coating in wet, humid weather.
Common Symptoms
Rear camera mirror screen goes black
Grainy, pixelated or distorted image
Image out of focus, especially at night or in rain
Mirror feed cuts out intermittently
How to Fix
Clean and inspect the camera lens and wiring first, then use the symptom and module diagnostics to distinguish the inside rearview-mirror display from the roof-mounted camera. No single retail part safely covers both branches or every CT6 option code.
On the 2016-2020 Cadillac CT6, cT6 owners report the 12-volt battery going flat after the car sits for a few days, sometimes flat enough that the electronic shifter and door handles will not respond and the car needs a jump. GM documents a cycling battery draw on 2016-2020 CT6 vehicles in preliminary information bulletin PIC6359A: the keyless entry control module repeatedly wakes and polls for the key fob transmitters to support the approach-lighting feature, and the repeated wake cycles keep total draw above the acceptable sleep threshold. Other modules that fail to time out (infotainment, security) produce the same symptom, so the offending module has to be identified rather than assumed.
Common Symptoms
Dead battery after the car sits several days
Repeated jump-starts needed
Electronic shifter or door handles unresponsive
Multiple warning messages on wake-up
Battery saver mode message
How to Fix
Measure and isolate the key-off draw before replacing anything. Apply the applicable module calibration first; replace and program a module only when the draw remains and the diagnostic branch confirms it.
On the 2016-2020 Cadillac CT6, cT6 owners report the radiator cooling fans running at high speed all the time — including after shutdown — with the coolant temperature gauge reading cold, and in many cases weak heater output and the A/C refusing to engage. The root cause is a thermostat that fails stuck open. The engine never reaches its target coolant temperature in the calibrated time, so the ECM sets P0128 (coolant temperature below thermostat regulating temperature), defaults the temperature gauge to the cold end, commands the A/C off, and commands the cooling fans on as a protective default. Owners frequently mistake this for a fan relay, a fan module or a bad temperature sensor and replace those first.
Cooling fans run constantly, including after shutdown
Temperature gauge reads cold or does not rise
A/C will not engage
Poor heater output
Check engine light
How to Fix
Confirm P0128 and commanded-versus-actual coolant temperature, then replace the thermostat housing for the exact engine and bleed the cooling system. The CT6 uses different housings across its 2.0L, V6 and 4.2L engines.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
General Motors LLC (GM) is recalling certain 2020 Cadillac CT6 vehicles equipped with dealer-installed accessory 20" x 8.50" wheels (RPO 5JO or SHH). The tire pressure monitoring system (TPMS) sensors use the incorrect wireless radio frequency and cannot illuminate the low pressure warning light when the tire pressure drops below the recommended level. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard (FMVSS) number 138, "Tire Pressure Monitoring Systems."
Campaign #19V73100015/10/2019
POWER TRAIN:AUTOMATIC TRANSMISSION
General Motors LLC (GM) is recalling certain 2019-2020 Cadillac CT6, 2020-2021 CT4, CT5, and 2020-2022 Chevrolet Camaro vehicles equipped with a 10-speed transmission. The transmission may become damaged internally and cause the wheels to lock-up.
Campaign #25V14800006/03/2025
SERVICE BRAKES, HYDRAULIC:ANTILOCK/TRACTION CONTROL/ELECTRONIC LIMITED SLIP:ABS WARNING LIGHT
General Motors LLC (GM) is recalling certain 2019 Chevrolet Silverado 1500, Cadillac CT6, and GMC Sierra 1500 vehicles. Due to an Electronic Brake Control Module (EBCM) software error, the vehicle's Electronic Stability Control (ESC) and Antilock Brake System (ABS) may become disabled. Furthermore, if this specific error occurs, the vehicle's diagnostics will not illuminate the instrument cluster ESC and ABS malfunction warning lights. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard (FMVSS) number 126, "Electronic Stability Control" and 135, "Light Vehicle Brake Systems."
Campaign #19V88900012/12/2019
EXTERIOR LIGHTING:TURN SIGNAL:SWITCH
General Motors LLC (GM) is recalling certain 2019 Cadillac CT6 vehicles. Rotation of the steering wheel will not automatically cancel the turn-signals from flashing. As such, these vehicles fail to comply with Federal Motor Vehicle Safety Standard (FMVSS) number 108, "Lamps, Reflective Devices and Associated Equipment."
Campaign #19V11700021/02/2019
SEAT BELTS:REAR/OTHER
General Motors LLC (GM) is recalling certain 2018-2019 Cadillac CT6, Escalade ESV, Chevrolet Suburban, Volt, and GMC Yukon XL vehicles. Certain second-row or third-row rear seatbelts retractor assemblies may not automatically lock when the seatbelt is fully pulled out of the retractor, possibly preventing a child seat from being properly secured. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard (FMVSS) number 208, "Occupant Crash Protection."
According to Au7o's research across NHTSA recalls, manufacturer TSBs, and owner forum reports, the 2020 Cadillac CT6 has 5 documented issues. The most frequently reported are: 10-Speed Transmission Damage Can Cause Wheel Lock-Up (Recall 25V148), Parasitic Battery Drain From Keyless Entry Module Polling for Approach Lighting, Failed Thermostat Sets P0128, Forces Cooling Fans to Run Constantly and Disables the A/C. Of these, 1 is rated critical and should be addressed promptly.
Is the Cadillac CT6 reliable?
The 2020 Cadillac CT6 has 5 known issues compiled from NHTSA recalls, manufacturer TSBs, and owner forum reports. 1 issue is rated critical: 10-Speed Transmission Damage Can Cause Wheel Lock-Up (Recall 25V148). Prospective buyers should inspect for these issues and factor potential repair costs into their purchase decision. Regular maintenance following the manufacturer's schedule helps prevent many common problems.
How much does it cost to fix common Cadillac CT6 problems?
Repair costs for known Cadillac CT6 issues range from $0 to $1,500, depending on the specific problem and whether you choose DIY or professional repair. Au7o provides step-by-step DIY maintenance guides that can help reduce repair costs.
What is the 2019-2020 Cadillac CT6 10-Speed Transmission Damage Can Cause Wheel Lock-Up (Recall 25V148)?
Certain 2019-2020 Cadillac CT6 vehicles equipped with a 10-speed transmission can develop internal transmission damage that may cause the wheels to lock while driving. Severity: high.
What is the 2016-2020 Cadillac CT6 Parasitic Battery Drain From Keyless Entry Module Polling for Approach Lighting?
CT6 owners report the 12-volt battery going flat after the car sits for a few days, sometimes flat enough that the electronic shifter and door handles will not respond and the car needs a jump. GM documents a cycling battery draw on 2016-2020 CT6 vehicles in preliminary informati… Repairs typically run $150-$900. Severity: medium.
What is the 2016-2020 Cadillac CT6 Failed Thermostat Sets P0128, Forces Cooling Fans to Run Constantly and Disables the A/C?
CT6 owners report the radiator cooling fans running at high speed all the time — including after shutdown — with the coolant temperature gauge reading cold, and in many cases weak heater output and the A/C refusing to engage. The root cause is a thermostat that fails stuck open. Repairs typically run $350-$800. Severity: medium.
What is the 2020 Cadillac CT6 Incorrect-Frequency TPMS Sensors on Dealer-Installed 20-Inch Wheels (Recall 19V731)?
GM recalled 2020 Cadillac CT6 sedans fitted with dealer-installed accessory 20 x 8.5-inch wheels (RPO 5JO or SHH) under NHTSA campaign 19V731. The tire pressure monitoring sensors mounted in those accessory wheels transmit on the wrong radio frequency, so the car's TPMS receiver… Repairs typically run $0-$0. Severity: medium.
What is the 2016-2020 Cadillac CT6 Rear Camera Mirror Module Failure — Blank, Blurry or Distorted Streaming Mirror Image?
The CT6's rear camera mirror streams a live video feed from a roof-mounted rear camera onto the mirror glass. Owners report the feed going blank, showing a grainy, pixelated or heavily distorted picture, or losing focus so badly at night and in rain that the mirror is unusable. G… Repairs typically run $400-$1,500. Severity: low.
Content on this page was compiled with AI assistance using NHTSA complaints, TSBs, owner reports, and public automotive data. While we strive for accuracy, this information may contain errors. Always verify repair procedures and specifications with your vehicle's service manual or a qualified mechanic.
